This invention relates to a vibratory apparatus for attenuating static friction in an altimeter having an indicator driven by a low power sensor.
Since such low power sensors are responsive to the changes in pressure associated with changes in altitude, it is necessary that each increment of torgue developed by these sensors be transmitted to an output pointer without modification to assure that indicated altitude is the actual altitude.
Initially, it was thought that the vibrations produced within an aircraft would be sufficient to prevent static friction. However, from observation it was observed that the indicator pointer movement was erratic, especially when the aircraft was operating on a smooth glide path.
Thereafter, it was suggested that a rotating eccentric vibrator or electrically driven thumper be attached to the housing of the altimeter to attenuate static friction. While operating successfully to reduce static friction, such devices produce objectionable noise in the cockpit area of the aircraft, suffer from mechanical wearout, and thus fail to produce uniform results after a limited time period.